how do you know a bad tube?

Larryken
Got it. Thanks. i never did notice much of a diff in the VK5i, from swapping from side to side... as the thing biases itself each time... but then I must never have had a severely poor tube. the biggest/best thing in that unit I found was having all the same tubes in the signal path, and play with something in the shunts. ultimately, i found that the simplest and best way to outfit the unit.

Larryi
it sure does seem the way. Another set entirely. Geezzz Louise.

See I was thinking there is some really neat gizmo out there that one can plug a tube into for just strength or short testing. Like a wiggins voltmeter.... and I'd not have to spend hundreds for a tester i probably cant read well enough anyways... and need to periodically recalibrate.

Oil well. Thanks. Thanks very much... of course if there is someone out there who knows of a simple tester which does a good job is sturdy, with B-I-G meters, and seldom requires calibration...I would like to hear about it, and where it is available.

A couple of the tube amps I am thinking about have quite a number of tubes in them... and some singles in there as well... an affordable tester I could use does seem relevant to have if you're going to pursue an all tube system, doesn't it?.

Tube tester.

Blindjim. I think others have addressed your tube dilema very well. I`m curious, after reading your "what would your next upgrade be" thread on your system page, what your impression of Herbies tweaks is and how you`re doing with the room tuning.

I`m a big "Herbies" fan and have implemented (one at a time) every dampening tweak that Steve offers. Each implimentation isolated instruments more and more and brought a more realistic soundstage. I`m very happy with the results.

I`m also doing some room tuning and am curious as to how you`re coming along with yours. Maybe you could update your other thread (if you feel like it). It was an interesting read for me, and I assume, others.

I don't know of any kind of simple and cheap tube tester that will reliably tell you when a tube is going bad. Most testers are not cheap and many require calibration and maintenance.

Also, a tube can begin to go bad in ways that certain testers will not be able to detect. Even a good tester that measures transconductance, may give you an idea of the strength of the tube, but not other conditions, such as noise. I had a small signal tube, an EH 6sn7, that became gassy. It tests spectacularly strong for transconductance, but my tester (not cheap) also tests for gassy condition and it showed that this tube was horrible in that respect.

Capt369
i apologize for not promptly or even regularly giving some followup there. i will.

Larryi
yeah. i was just hoping aginnst hope, I had overlooked something easy, or some other fashion or method going forward to check things out. if I do wind up with a pair of tube mono blocks as well, and something goes awry, I'll have a coniption fit trying to swap in and out tubes from a second set as was mentioned previously... but is a good idea. one I have followed in the past. one also that is a mite pricey. As I chose then to get them all from reputable dealers and none have actually gone bad on me Save the first set i got which came with the preamp, but were disposed of shortly thereafter. man. if there is anything I hate to do it's trash a tube that still lights up, and it is tiresome and expensive to send them out to have checked. Not to mention the waiting period (s).

OK. A second set instead of a tester. Super.

Does anyone make one tube monos?